In this study, the whole mitochondrial genomes of Physogyra lichtensteini and Plerogyra sinuosa have been sequenced for the first time. The length of their assembled mitogenome sequences were 17,286 bp and 17,586 bp, respectively, both including 13 protein-coding genes, two tRNAs, and two rRNAs. Their mitogenomes offered no distinct structure and their gene order were the same as other typical scleractinians. Based on 13 protein-coding genes, a maximum likelihood phylogenetic analysis showed that Physogyra lichtensteini and Plerogyra sinuosa are clustered in the family Plerogyridae, which belongs to the “Robust” clade. The 13 tandem mitogenome PCG sequences used in this research can provide important molecular information to clarify the evolutionary relationships amongst stony corals, especially at the family level. On the other hand, more advanced markers and more species need to be used in the future to confirm the evolutionary relationships of all the scleractinians.

Montipora vietnamensis Veron, 2000 (Cnidaria, Anthozoa, Scleractinia, Acroporidae) is an uncommon, but distinctive species of stony coral. The complete mitochondrial genome of M. vietnamensis was sequenced in this study for the first time, based on 32 pairs of primers newly designed according to seven species in the family Acroporidae. The mitogenome of M. vietnamensis has a circular form and is 17,885 bp long, including 13 protein-coding genes (PCGs), 2 tRNA (tRNAMet, tRNATrp), 2 rRNA genes and a putative control-region. The base composition of the complete mitogenome was 24.8% A, 14.2% C, 24.2% G and 36.8% T, with a higher AT content (61.6%) than GC content (38.4%). Based on 13 protein-coding genes, a Maximum Likelihood phylogenetic analysis showed that M. vietnamensis is clustered in the genus Montipora which belongs to the family Acroporidae. More stony coral species should be sequenced for basic molecular information and to help confirm the taxonomic status and evolutionary relationships of Scleractinia in the future.

A Gram–straining–negative, facultatively anaerobic, motile by means of a polar flagellum and rod-shaped marine bacterium, designated S4M6T, was isolated from surface seawater collected in Dongshan Bay (Fujian, PR China). Phylogenetic analysis based on 16S rRNA genes, phylogenomic analysis of single-copy gene families and whole genome data indicated that S4M6T represented a member of the genus Vibrio . The closest phylogenetic relatives of S4M6T were Vibrio marisflavi CGMCC 1.8994T (97.8 % 16S rRNA gene sequence pairwise similarity), Vibrio variabilis LMG 25438T (96.9 %), Vibrio gangliei SZDIS-1T (96.2 %) and Vibrio aestivus M22T (96.1 %). The growth of S4M6T occurred at 15–35 °C (optimum 28 °C), pH 4.0–9.0 (optimum 5.0–7.0) and in the presence of 2–5 % (w/v) NaCl (optimum 3 %). The predominant fatty acids (>10 %) are C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 :  1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 :  1ω6c). The DNA G+C content of the assembled genomic sequences was 43.4 % for S4M6T. Average nucleotide identity (ANI) values between S4M6T and the reference species were lower than the threshold for species delineation (95–96 %); in silico DNA–DNA hybridization further indicated that S4M6T had less than 70 % similarity to its relatives. On the basis of the polyphasic evidence, strain S4M6T is proposed to represent a novel species of the genus Vibrio , for which the name Vibrio sinus sp. nov. is proposed. The type strain is S4M6T (= KCTC 92312T= MCCC 1K06167T).

Reef-building coral species of the order Scleractinia play an important role in shallow tropical seas by providing an environmental base for the ecosystem. The molecular data of complete mitochondrial genome have become an important source for evaluating phylogenetic and evolutionary studies of Scleractinia. Here, the complete mitogenome of Homophyllia bowerbanki (Milne Edwards and Haime, 1857), collected from Nansha Islands of the South China Sea, was sequenced for the first time through a next-generation sequencing method. H. bowerbanki is the first species of its genus for which the mitogenome was sequenced. This mitogenome was 18,154 bp in size and included two transfer RNA genes (tRNAs), 13 protein-coding genes (PCGs), and two ribosomal RNA genes (rRNAs). It showed a similar gene structure and gene order to the other typical scleractinians. All 17 genes were encoded on the H strand and the total GC content was 33.86% in mitogenome. Phylogenetic analysis (maximum likelihood tree method) showed that H. bowerbanki belonged to the “Robust” clade and clustered together with other two species in the family Lobophylliidae based on 13 PCGs. The mitogenome can provide significant molecular information to clarify the evolutionary and phylogenetic relationships between stony corals and to facilitate their taxonomic classification; it can also support coral species monitoring and conservation efforts.